99 patients suffering from therapy-resistant depression, meaning they did not improve when previously taking anti-depressant drugs or electroconvulsive therapy, were given 5-HTP at an average of 200 mg per day combined with the peripheral decarboxylase inhibitor, carbidopa. Complete recovery was seen in 43 of 99 patients, and another 8 had significant improvement. 5-HTP was effective so quickly, restored normal mood so fully, and did so with minimal side effects, that it should be regarded as an excellent anti-depressant.
The researcher concluded:
“This treatment produced an astonishing recovery without side effects in some 50% of patients.”